Dysuria can be largely divided into emptying disorder due to inability to urinate with sufficient force at the time of emptying the bladder, and bladder-filling disorder due to inability to retain urine during the filling time. Presently, α1 blocker is frequently used for treating the emptying disorder and anticholine agent, for treating bladder-filling disorder. These drugs, however, have such defects as insufficient long-term therapeutic effect or reduction in quality of life (QOL) induced by side effect, and development of drugs having new activity mechanism different from the conventional approach, for example, drugs utilizing potassium channel opening activity, cyclic guanosine-3′,5′-monophosphate (cGMP) degradation inhibiting activity, are in demand.
cGMP plays an important role in variegated cellular phenomena such as smooth muscle relaxation, memory and learning function control, photoreaction of retina, cell proliferation, immunoreaction and the like, and drop in intracellular cGMP concentration causes disorder in cell functions. Synthesis of cGMP by nitrogen monoxide (NO)-cGMP system and degradation of cGMP by PDE system are continually progressing in the cells each at a constant rate and good balance of the two are maintained in normal cells. Whereas, within the cells under various states of disorder, function of the NO-cGMP system lowers to render the cGMP synthesis level in the cells low. Because the cGMP degradation in the cells progresses at a fixed rate in the meantime, cGMP concentration in the affected cells becomes low. It is expected, therefore, prevention of cGMP degradation in the cells to redress the reduction in intracellular cGMP concentration would be useful for treating or preventing diseases.
While there are many types of PDE, those which specifically decompose cGMP are type 5 (PDE5), type 6 (PDE6) and type 9 (PDE9). Of these, PDE9 shows the least Km value (J. Biol. Chemistry, Vol. 273, No. 25, 15559-15564 (1998), has high affinity to cGMP and is considered to participate in degradation of cGMP with particular significance.
Heretofore, pyrazolopyrimidine derivatives are known as the compounds exhibiting PDE9-inhibiting activity, and as patent literature relating to the derivatives, for example, there are PCT International Publication WO 03/037432 Pamphlet disclosing their utility for treating insulin-resistant diseases, WO 03/037899 Pamphlet disclosing their utility for treating cardiovascular disorder, and WO 2004/018474 Pamphlet disclosing their utility for improving perception, learning and memory functions.
Whereas, thienopyrimidine derivatives having PDE9-inhibiting activity are heretofore entirely unknown, and there is no existing literature discussing relevancy between PDE9-inhibiting activity and therapeutic effect on dysuria.
Screening library of Ambinter Co. posts a thienopyrimidine derivative represented by the following formula:
but catalogues, pamphlets and the like materials issued by the same company give no information including activity on this compound.